SPECTROSCOPIC AND POLAROGRAPHIC INVESTIGATIONS - COPPER(II)-PENICILLIN DERIVATIVES

Copper(II) derivatives of penicillins (benzypenicillin, phenoxymethyle nepenicillin, ampicillin, amoxycillin and carbenicillin) have been pre pared. Copper(II) ions promote hydrolysis of penicillins (L) to corres ponding penicilloic acids (L) owing to beta-lactam group. Coordinatio n compounds isolated under equilibrium conditions showed stoichiometri es of the type CuL, CuL2*, and CuL3*, Two compounds with molar metal to ligand ratio 1:1 and 1:3 are aqueous soluble and interactions at mo lar ratio 1:2 result in precipitate formation. The solubility of the p recipitates undergoes no changes in a broad pH region. It takes place only in highly acidic or alkaline media. The infrared spectra suggest that penicillins behave as monoanionic bidentate ligands coordinating the Cu(II) ion through the carboxylic group. (C) 1997 Elsevier Science B.V.